sand-boxer/workplans/SAND-WP-0015-bwrap-runtime-and-private-state.md

---
id: SAND-WP-0015
type: workplan
title: "Provide a pinned bwrap rein runtime and private state"
domain: infotech
repo: sand-boxer
status: blocked
flavor: implementation
owner: codex
topic_slug: bwrap-runtime-and-private-state
created: "2026-09-05"
updated: "2026-09-27"
state_hub_workstream_id: "d3f12387-fd23-58f0-b979-9c811507614d"
---

# Provide a pinned bwrap rein runtime and private state

Implement the runtime prerequisites returned by Glas in `GLAS-WP-0012` and
`docs/local-profile-acceptance.md`. Continue owner work `SAND-WP-0014-T05` and
live residual `GLAS-IN-0002`. Runtime startup is a separate acceptance gate
from credential delivery, enforced provider egress, and a real model task.

## Mount an owner-selected, digest-pinned Python runtime

```task
id: SAND-WP-0015-T01
status: done
priority: high
state_hub_task_id: "93e4aad8-ba9b-5850-93d4-b5bf78ac8978"
```

Add exact artifact verification to trusted extension configuration and mount
the standalone runtime read-only at a fixed namespace path. Reject altered
content/modes, unexpected files, escaping symlinks, special files, and source
or workspace overlap. A caller cannot choose runtime paths through exec input.
Provide a non-editable rein-aharness/llm-connect bundle builder with recorded
source revisions and resolved dependency versions.

Completed 2026-09-05. `extensions/runtime.py` verifies complete artifact
contents/modes before a read-only mount; the builder installed committed
rein-aharness `1429db5` and llm-connect `0056094` without editable source paths.
Candidate digest and source/package evidence are in `docs/bwrap-runtime.md`.

## Keep writable runtime state outside the repository

```task
id: SAND-WP-0015-T02
status: done
priority: high
state_hub_task_id: "c8a689f8-bdf2-57a2-8521-a1c0ca44e750"
```

Create private mode-0700 HOME/config/cache/state/tmp directories within the
namespace, preserve them across exec requests, and remove them with teardown.
Keep the command environment sanitized and disable Python user-site/bytecode
writes. Fail closed on profile network/setup-credential declarations that the
current bwrap implementation cannot honor.

Completed 2026-09-05. Mode-0700 namespace HOME and XDG/TMP directories sit
outside the copied Git tree. Explicit runtime PATH selection remains owner
controlled. Unsupported egress/default-allow and setup credentials now refuse
before workspace creation; regression tests cover these boundaries.

## Verify the real rein runtime and owner regression paths

```task
id: SAND-WP-0015-T03
status: done
priority: high
state_hub_task_id: "1a3002f6-c6a8-59d0-9d38-942028419de5"
```

Run `make check`, the existing authenticated cross-request owner smoke, and a
real runtime startup smoke. Verify the actual rein CLI and adapter imports,
read-only runtime, private HOME, clean worktree, absent source, loopback-only
network, and teardown. Keep the production Glas profile blocked.

Completed 2026-09-05. `make check`: lint clean, 132 tests passed. Authenticated
owner API smoke `223db65b` returned HTTP 200 and proved exact consumer identity,
stdin delivery, absent source, loopback-only network and complete teardown.
Pinned runtime smoke `d4de9531` ran the actual rein CLI and imported its Claude
adapter, proved read-only runtime/private HOME/clean worktree, retained private
state across a second exec, and removed the workspace. No model call or
credential acquisition occurred; T04 remains waiting.

## Resolve Claude credentials, enforced egress, and production acceptance

```task
id: SAND-WP-0015-T04
status: wait
blocked_on: message-from:railiance-platform
blocking_reason: "Credential owner railiance-platform/OpenBao with rein-aharness must establish a Claude-compatible route and delivery/revocation contract."
priority: high
state_hub_task_id: "58817ef6-76d9-5e34-908f-c024e6c99f93"
```

The 2026-09-05 routing lookup found no concrete Anthropic/Claude workload lane.
The generic OpenBao template is not a delegable lane; the OpenRouter AppRole
belongs to another rein. Credential owner railiance-platform/OpenBao plus
rein-aharness must establish a concrete Claude-compatible route and delivery/
revocation contract before values can be requested or supplied to the runtime.

Sand-boxer must then implement the matching enforced provider egress contract
(including DNS/TLS and denied-destination proof) and pin/deploy the actual
Claude executable. No unrestricted-network or interactive-login substitute is
permitted. Review the deployed runtime/profile with Glas, run its real-rein
acceptance fixture, and update only the proven profile's readiness. No
production schedule is enabled by the runtime-startup smoke.

This task and SAND-WP-0014-T05 remain open until those gates pass. The detailed
return contract and runtime proof are in `docs/bwrap-runtime.md`; the live
cross-repo residual remains `GLAS-IN-0002`.

## 2026-09-05 transport implementation evidence

T04 remains waiting on owner machine authentication, protected credential
delivery, pinned Claude startup and the real model proof. CCR-2026-0016 custody
is confirmed by a metadata-only check of live version 2; no value was read.
HTTPS egress is now implemented as an exact owner/profile allowlisted CONNECT
proxy while retaining an isolated network namespace. Non-secret live smoke
sandbox e290e788 verified provider TLS response, undeclared destination and
direct-IP denial, and proxy/workspace teardown. See docs/bwrap-egress.md.

## 2026-09-05 credential transport owner return

Owner-bound exec-env transport is implemented and proved with a synthetic
provider in real sandbox 0e5fb35a. Exact route/profile/project/actor/run binding,
child-only key injection, pre-truncation redaction, next-exec absence and teardown
pass. No real key read or production profile activation. See docs/bwrap-credentials.md.
SECRETS-WP-0009 now owns native AppRole adoption for CCR-2026-0016, including
a data-only consumer read policy. Its production exec refuses before OpenBao
until SECRETS-WP-0007-T04 and SECRETS-WP-0008-T02/T06 deliver canonical
authorization/consume and service authority. T04 remains waiting on that live
owner path, the pinned Claude executable and real model acceptance.

## 2026-09-06 combined-runtime candidate returned to Glas

Answered the GLAS-WP-0015 handoff. Added candidate profile
`profile.claude-agent-dev-proof` version 1.1.0 (`ext.bwrap`, localhost-only,
`default: deny` with declared `api.anthropic.com:443`) for GLAS-WP-0012 review.
The committed profile grants no egress by itself: `ext.bwrap` refuses it unless
the owner extension config allowlists the destination, and a regression test now
asserts that fail-closed default. `make check`: lint clean, 172 tests passed.

Resolved the differing project examples in favour of the acceptance runner's
`actor: agt` / `project: glas-local-proof`, and bound the documented credential
route to that single project rather than broadening it. The full return contract
— profile id/revision, host scope, consumer tuple, runtime digest and mount
paths, declared egress, and the value-free denial/cleanup receipts — is in
`docs/bwrap-runtime.md`.

T04 stays `wait`: the concrete Claude credential lane and delivery/revocation
contract, owner machine authentication, the pinned Claude executable with its
own proxy startup proof, and the real-model acceptance are still operator and
upstream-owner gated. Provider workspace scope and spend limit remain operator
inputs. `SAND-WP-0014-T05` remains open on the same gates.


## Package and prove the pinned Claude executable independently of custody

```task
id: SAND-WP-0015-T05
status: done
priority: high
state_hub_task_id: "f0163cda-b581-56a0-a0dd-9c8a436f5bbe"
```

Split the independent executable packaging/startup portion from T04 so credential
custody does not hide completed local runtime work. Implement explicit binary
pinning, reject mismatches/host wrappers, and prove actual startup with the
broker proxy environment and complete cleanup. T04 retains protected deployment,
credential adoption and real-provider acceptance.


## Pinned Claude candidate and isolated startup — 2026-09-06

The builder now accepts `--claude-binary`, `--claude-sha256` and
`--claude-version` together. It requires a regular native ELF file, verifies the
exact copied bytes, refuses symlinks/wrappers/mismatches and existing destination
files, and copies only the executable as bin/claude mode 0755. The expected
version is metadata until the sandbox smoke checks the actual output. No
interactive HOME, provider key or login state is copied.

Candidate provenance: the explicitly selected installed native release
`/home/worsch/.local/share/claude/versions/2.1.263`, SHA-256
`26d020351e8112f4006790f3cfce43b4c9df0c1bb1d0e542364d64151b81d5ba`.
This is a digest pin of the selected local artifact, not an upstream signature
verification claim. Complete runtime candidate:
`/tmp/sandboxer-claude-runtime-20260906`, SHA-256
`5cf9a16c5d77a16bdb2cb5b3df06ea655356bc2d44741791e3fedfee20d7e922`.
Mount remains `/opt/sandboxer/runtime`; Claude is `/opt/sandboxer/runtime/bin/claude`.
Rein sources remain 1429db5 / llm-connect 0056094; resolved dependency versions
are recorded in the evidence. Rebuilding may resolve different dependencies;
the complete digest pins this artifact, not future builds.

Sandbox f8821ec2 ran real `claude --version` -> `2.1.263 (Claude Code)` plus rein
CLI/import checks, with owner allowlisted provider egress and HTTPS_PROXY set
by the broker. Runtime read-only, private 0700 HOME/state persistence, clean Git,
absent source and loopback-only interfaces passed; workspace and proxy removed.
`make check`: lint passed, 175 tests passed.

Evidence: docs/evidence/SAND-WP-0015-claude-startup-2026-09-06.json.
Reproduce with the builder options above and `scripts/smoke-bwrap-runtime.py
--runtime-path <candidate> --runtime-sha256 <digest> --claude-version 2.1.263`.

Limits: `--version` proves startup with the proxy environment, not that Claude
has sent a provider request through it. No credential acquisition or model run.
The /tmp candidate is not production placement; protected artifact installation,
owner configuration, credential adoption and real-model proof remain T04 gates.


## Install the pinned runtime in the local owner's protected store

```task
id: SAND-WP-0015-T06
status: done
priority: high
assignee: the-custodian
state_hub_task_id: "f85f54c9-1081-5d0c-95ad-aca20ede8d66"
```

HFACT-WP-0001-T04 consumes this independent installation return. Reuse the
already verified combined candidate with digest
`5cf9a16c5d77a16bdb2cb5b3df06ea655356bc2d44741791e3fedfee20d7e922`;
do not rebuild resolved dependencies. Publish it under the local owner's
private artifact store, verify exact copied content/modes and refusal of unsafe
or corrupted destinations, and prove startup/read-only access/teardown through
the installed path. The owner remains trusted; this is not root-owned storage.
T04 retains real credential adoption, owner configuration, model acceptance
and production placement. No credential route or profile is activated here.

`scripts/install-bwrap-runtime.py` installs below the owner's home into a
mode-0700 store, verifies before and after copying, preserves artifact modes
and internal symlinks, serializes publishers and never overwrites a published
artifact. Existing modified artifacts are refused rather than repaired silently.
Group/other-writable ancestors, unsafe permission bits and store aliases refuse.
Unit tests cover integrity, idempotence, copy-time corruption and access modes.


T06 completed 2026-09-08 on bnt-lap001, local owner UID 1000. Installed the
unchanged 358-entry / 245176062-byte candidate at
`/home/worsch/.local/share/sandboxer/runtimes/5cf9a16c5d77a16bdb2cb5b3df06ea655356bc2d44741791e3fedfee20d7e922`.
The private store is mode 0700; the installing owner remains trusted. A root-owned
system installation was not claimed or required for this local owner contract.
The installed-path sandbox smoke `51b59587` passed real Claude 2.1.263 and rein
startup, read-only mount, private state persistence, clean worktree, absent source,
loopback-only interfaces and complete workspace/proxy teardown. No model call
or credential acquisition occurred. `make check`: lint clean, 188 tests passed.
Two existing tests require the checkout directory name `sand-boxer`; the final
full check used that canonical basename. Evidence:
`docs/evidence/SAND-WP-0015-protected-local-install-2026-09-08.json`.
T04 retains owner execution configuration, native credential/egress and real-model
acceptance; Railiance installation needs its own target-specific return.

## 2026-09-09 factory metered route source return

Implemented the trusted, ephemeral Messages route described in
[docs/bwrap-messages-route.md](../docs/bwrap-messages-route.md). Actual local
bwrap owner transport proves provider key/ledger separation, direct-route denial,
revocation and teardown; rein also proves metered request plus commit import and
close replay. `make check`: lint clean, 199 passed. T04 remains waiting for the
admitted provider-to-owner bootstrap, updated protected runtime/profile, Railiance
placement, live compatibility and G0. Existing child-provider-key/direct-CONNECT
proofs do not admit this different credential holder or metered profile. No CCR,
secret read, deployment or paid request was performed.

## 2026-09-09 standalone owner packaging and runtime selection

Added frozen-lock owner build mode for the matched rein/llm/Glas/sandboxer set,
with non-editable installation and recorded lock/source/package pins. Sand-boxer
wheels now carry their profile and extension definitions, fixing a bwrap owner
failure that source-checkout tests could hide. The trusted Messages binding can
select the digest-pinned runtime without adding an API or profile override.
`make check`: lint clean, 205 passed. Existing standalone workload builds remain
supported. See docs/bwrap-runtime.md and rein's docs/owner-bootstrap.md.

The project's `evidence/2026-09-09-owner-bootstrap.json` records the actual candidate
build and isolated installed-interpreter/CLI proof. T04 remains wait for accepted
credential-to-owner delivery, current protected installation and Railiance placement,
provider compatibility and G0. Source packaging does not reopen completed T01-T03,
T05-T06, broaden the old CCRs or activate the previously installed 2.1.263 artifact.

The first standalone candidate exposed a stale cached local wheel despite current
Git metadata. Owner builds now refresh all local distributions and compare every
installed package source/definition file with its tracked source; stale, missing or
extra files refuse the build. Four content-conformance regressions cover that gap.


## 2026-09-27 installed launcher defect and guarded correction

REINAH-WP-0003's single admitted attempt completed native provider/companion
apply, verify and exec, including scoped-token revocation. The claimed job
`6efa9436-6a91-47c0-94e5-b31b5a0e7e3a` failed before any provider request
reservation. The sandbox was destroyed and the source repository is unchanged.
The parent EUR 10 liability remains held for explicit reconciliation; no retry
or replacement authority is inferred.

Installed artifact `b6e4e8a4` contains uv-generated three-line shell launchers
that still reference a vanished temporary build interpreter. The builder had
only rewritten direct Python shebangs. Fixed both generated forms and added
actual relocation/execution tests for direct, long and space-containing build
paths, plus refusal of unknown governed launchers. Builder tests: 12 passed;
focused lint passes. Rein's real installed bwrap probe reproduces both broken
entrypoints at exit 127 with zero provider forwards; its new bootstrap checks
refuse the malformed artifact before claiming.

T04 remains `wait` and this plan stays `blocked`: replacement artifact build/
admission and a separately authorized successful model/tool/commit proof remain.
The existing SAND-WP-0015 / REINAH-WP-0003 / SECRETS-WP-0009 records retain the
work. No new task or workplan. Detailed non-secret receipts are in rein-aharness
`docs/evidence/2026-09-27-metered-*.json`.